Comparison on efficiency factors of F and C types of fly ashes

Yıldırım, Hasan; Sümer, Mansur; Akyüncü, Veysel; Gürbüz, Emrah

doi:10.1016/j.conbuildmat.2010.12.009

Cited by 31 publications

(9 citation statements)

References 8 publications

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“…Fly ash, either with low calcium (class F) or high calcium (class C) content, is a material rich in silica and alumina, and can be used as a precursor in making geopolymer. The activation of the source material occurs in the presence of a highly alkaline solution, commonly a combination of sodium hydroxide and sodium silicate (Wattimena et al 2017;Yildirim et al 2011). The ratio and content of the two alkalis determine the characteristics of the geopolymer concrete (Arioz et al 2012;Hardjito et al 2004;Mustafa et al 2011;Rangan 2010;Rattanasak and Chindaprasirt 2009;Thunuguntla and Gunneswara Rao 2018).…”

Section: Introductionmentioning

confidence: 99%

Fresh and Hardened Properties of High Calcium Fly Ash-Based Geopolymer Matrix with High Dosage of Borax

Antoni

Purwantoro

Suyanto

et al. 2019

Iran J Sci Technol Trans Civ Eng

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Your article is protected by copyright and all rights are held exclusively by Shiraz University. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com". AbstractGeopolymer is synthesized by mixing material rich in alumina and silica, such as fly ash, with a highly alkaline solution to form a hardened matrix. However, when using high calcium fly ash as a precursor, a flash set frequently occurs, i.e., the mixture hardens very rapidly before casting can be completed. The use of borax as an additive has been reported due to its potential to prolong the setting time. In this study, the use of a significantly higher dosage of borax is explored. The results show that the addition of borax up to 20% of fly ash, by mass, into the alkaline solution prolongs the setting time by up to 90 min. Conversely, the addition of higher amounts of borax tends to decrease the compressive strength of the geopolymer, whereas adding a small amount of calcium oxide into the mixture increases the strength marginally, especially when the borax content is small. However, the amount of calcium oxide should be limited because at higher content, the effectiveness of borax to prolong the setting time is reduced.

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Section: Introductionmentioning

confidence: 99%

Fresh and Hardened Properties of High Calcium Fly Ash-Based Geopolymer Matrix with High Dosage of Borax

Antoni

Purwantoro

Suyanto

et al. 2019

Iran J Sci Technol Trans Civ Eng

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“…In addition, pozzolans were found to increase the strength and chemical resistance and reduce heat of hydration, permeability, porosity and alkali-silica expansion, which was another bonus [9]. The most frequently used pozzolans in the current concrete industry are industrial by-products such as fly ashes [10], silica fume [11], metallurgical slags [12] or waste glass [13]. Agricultural wastes, represented, for instance, by rice husk ash [14], bagasse ash [15] or sugar cane leaf [16], are being increasingly used, particularly in the regions where they are produced.…”

Section: Introductionmentioning

confidence: 99%

“…The most frequently used pozzolans in the current concrete industry are industrial by‐products such as fly ashes , silica fume , metallurgical slags or waste glass . Agricultural wastes, represented, for instance, by rice husk ash , bagasse ash or sugar cane leaf , are being increasingly used, particularly in the regions where they are produced.…”

Section: Introductionmentioning

confidence: 99%

Mechanical, durability and hygrothermal properties of concrete produced using Portland cement-ceramic powder blends

Kulovaná

Vejmelková

Keppert

et al. 2016

Structural Concrete

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Blended Portland cement‐ceramic powder binder containing up to 60 % fine‐ground waste ceramics from a brick factory is used in concrete mix design as an environmentally friendly alternative to the commonly used Portland cement. The experimental analysis of basic physical characteristics, mechanical and fracture‐mechanical properties, durability properties and hygrothermal characteristics shows that the optimal amount of ceramic powder in the mix is 20 % of the mass of blended cement. The decisive parameters in that respect are compressive strength, liquid water transport parameters and resistance to de‐icing salts, which are not satisfactory for higher ceramics dosage in the blends. In the case of other parameters studied, the limits for the effective use of ceramic powder are higher: 40 % for effective fracture toughness and specific fracture energy, 60 % for frost resistance and chemical resistance to MgCl2, NH4Cl, Na2SO4, HCl and CO2. The water vapour diffusion coefficient is found to increase with increasing ceramics content, which for wet envelopes can be considered as a positive feature, but may have a negative effect for dry envelopes. The thermal conductivity of all mixes increases fast with growing moisture content; differences of up to 50 % between the dry and water‐saturated state values are observed. This has to be taken into account in energy‐related calculations.

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“…On the other hand, for quantitative evaluation of the cementing efficiency of a SCM, the concept of cementing efficiency factor (CEF), which is defined as the mass of cement that can be substituted per unit mass of SCM added without affecting the strength or durability attribute under investigation, has been advocated for years [27][28][29]. This concept has been applied to evaluate the cementing efficiencies of various SCMs solely with respect to the strength and durability performances [11,[30][31][32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Cement Equivalence of Metakaolin for Workability, Cohesiveness, Strength and Sorptivity of Concrete

Chen

et al. 2020

Materials

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A series of concrete mixes with metakaolin (MK) content ranging from 0 to 30% and water/cementitious materials (W/CM) ratio varying from 0.30 to 0.50 were produced for performance testing. The results showed that adding MK up to 20% as ordinary Portland cement (OPC) replacement best improved the 28-day and 70-day cube strengths, whereas adding MK up to 30% as OPC replacement always increased the cohesiveness and decreased the sorptivity, but impaired the workability. Moreover, the cement equivalent factor (CEF), i.e. the equivalent mass of OPC per mass of MK added, for each performance attribute, including workability and cohesiveness, was evaluated. Whilst the actual CEF of MK was generally higher at a higher W/CM ratio and lower at a higher MK content, overall, the average CEFs were found to be 1.98, 2.17, 3.83, 1.93, 2.12, and 4.70 for slump, flow, cohesiveness, 28-day cube strength, 70-day cube strength, and sorptivity coefficient, respectively. These CEF values indicated that the MK is a highly effective cementitious material for improving the cohesiveness, strength, and durability. Moreover, it has been demonstrated that the CEFs for workability and cohesiveness are useful parameters in aiding the mix design of MK concrete.

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Comparison on efficiency factors of F and C types of fly ashes

Cited by 31 publications

References 8 publications

Fresh and Hardened Properties of High Calcium Fly Ash-Based Geopolymer Matrix with High Dosage of Borax

Fresh and Hardened Properties of High Calcium Fly Ash-Based Geopolymer Matrix with High Dosage of Borax

Mechanical, durability and hygrothermal properties of concrete produced using Portland cement-ceramic powder blends

Cement Equivalence of Metakaolin for Workability, Cohesiveness, Strength and Sorptivity of Concrete

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